Bishop of Alexandria from about 283 to 301 (Eusebius, "Chronicle", Ann. Abr. 2299, St. Jerome's version). In his time Achillas, who had been appointed presbyter at Alexandra, at the same time with Pierius, became celebrated (Euseb., "Hist. eccl.", III, xxxii). The celebrated letter of Theonas to Lucianus, chamberlain to Diocletian, which has often been quoted as giving such a lifelike description of the position of a Christian in the imperial Court has been pronounced, first by Batiffol and then by Harnack, to be a forgery. Their verdict is endorsed by Bardenhewer. It was first published from what purported to be a transcript made by Jérôme Vignier, by Dacherius in his "Spicilegium". Theonas is commemorated in the Roman Martyrology on 27 August. St. Athanasius in his apology to Constantinus speaks of a church dedicated by his predecessor, St. Alexander, to Theonas. The same church is alluded to in the "Act of SS. Pachomius and Theodorus".